Thursday, 25 October 2012

It was announced in 2003 that Kodak Technical Pan (or simply 'Tech Pan') had been discontinued. The announcement confirmed that the film had not been manufactured for some time and Kodak had been simply selling their existing stock: "The last Tech Pan coating was several years ago. Since that time, the old coating room has been shut down, the gels used in the product formulation have become obsolete, and we no longer manufacture the ESTAR support on which the 35 mm product was coated."

This is a black-and-white panchromatic film with extended red sensitivity.
It has micro-fine or extremely fine grain (depending on the developer
used), extremely high resolving power, and a wide contrast range for pictorial, scientific, technical, and reversal-processing applications.

Other applications such as slidemaking, copying, and microfilming that require high or moderately high contrast combined with fine grain and high resolving power

35mm Technical Pan with information leaflet

The leaflet gives a suggestion of exposure index settings and specific contrast indexes, from 16 to 200. For 'pictorial applications' it suggests an EI of 25 and development with Technidol. Having picked up a handful of rolls of Tech Pan from online auctions, on one of the sunniest days of the summer, I shot a roll of 35mm Tech Pan in my Werra camera, exposed at 25 EI. The bright conditions were needed to shoot hand-held with a low exposure index (using the 'sunny 16' rule at 25 EI, bright sunshine would indicate an exposure of 1/25th at f16, although I would tend to give bright sunshine in the UK one stop more exposure, which in practice meant shooting at 1/50th at f8 or 1/100th at f5.6).

The Massive Dev Chart has a section on discontinued film which includes Tech Pan. I developed the film in Rodinal 1:150 for 13 minutes at 20ºC, much longer than the recommended 7 minutes from the Massive Dev Chart. The results do appear overdeveloped, but a dilution of 1:150 for Rodinal seemed very low and the film was 16 years past its 'process before' date. However, judging by the results, the age of the film does not appear to have needed compensating for in development. At these high dilutions of Rodinal, consideration must be given to the capacity of the developing tank: Agfa, Rodinal's original manufacturer, recommended a minimum of 10ml per film, no matter the dilution used, which at 1:150 would mean a litre and a half of working solution. In practice a smaller amount of Rodinal works perfectly well; I used 6ml of developer to 900ml of water in a 3-reel Paterson tank.

The Banks of the Thames near Erith, Kodak Tech Pan (35mm), rated EI 25. Developed in Rodinal 1:150, 13mins at 20ºC.

In the scanned negatives, grain is not discernible. Presumably the grain is beyond the limit of the optical resolution of the flatbed scanners I've used. There is what looks like grain in the sky of some shots, but it appears to be noise introduced by the scanner. Having shot the photographs in bright sunlight, the images were always going to be high in contrast, regardless of the qualities of the film used. However, the blue skies reproduced darker in tone than might be expected with heightened contrast. In the section about pictorial photography in the data sheet, it states that "the extended red sensitivity has a haze-cutting effect in photographs
of distant landscapes and in aerial shots." As well as cutting haze, this extended red sensitivity presumably compensates for the usual over-sensitivity to the blue end of the spectrum that normal panchromatic film has.

I subsequently shot a roll of Tech Pan in medium format using my Baldalux camera, exposed at 25 EI and developed in Rodinal at 1:150 again, but for 12 minutes at 18ºC (roughly equivalent to 10 minutes at 20ºC; this film had a 'process before' date of 02/1995).

The contrast of the images is still there, perhaps a higher dilution
of developer would provide lower contrast (the Massive Dev Chart does list times for dilutions of 1:300 for Rodinal). Interestingly, the absence of discernible grain in the sky proved a problem in scanning and processing some of the negatives. In the photograph of the River Roding below, there is some banding in the image, noticeable in towards the top corners partly due to vignetting; attempts to reduce the vignetting using Photoshop's lens correction filter made the banding worse. The solution to banding in smooth tonal gradations in a digital image is to introduce noise, which I haven't done.